On the first day of battle, the Confederates struck with the intention of driving the Union defenders away from the Tennessee River and into the swamps of Owl Creek to the west, hoping to defeat Grant's Army of the Tennessee before it could link up with Maj. Gen. Don Carlos Buell's Army of the Ohio. The Confederate battle lines became confused during the fierce fighting, and Grant's men instead fell back in the direction of Pittsburg Landing to the northeast. A position on a slightly sunken road, nicknamed the "Hornet's Nest", defended by the men of Brig. Gens.Benjamin M. Prentiss's and W.H.L. Wallace's divisions, provided critical time for the rest of the Union line to stabilize under the protection of numerous artillery batteries. Gen. Johnston was killed during the first day's fighting, and Beauregard, his second in command, decided against assaulting the final Union position that night.

Reinforcements from Gen. Buell arrived in the evening and turned the tide the next morning, when he and Grant launched a counterattack along the entire line. The Confederates were forced to retreat from the bloodiest battle in United States history up to that time, ending their hopes that they could block the Union invasion of northern Mississippi.

Background and opposing forces

After the losses of Fort Henry and Fort Donelson in February 1862, Confederate General Albert Sidney Johnston withdrew his forces into western Tennessee, northern Mississippi, and Alabama to reorganize. In early March, Union Maj. Gen. Henry W. Halleck, commander of the Western Theater, responded by ordering Grant to advance his Army of West Tennessee (soon after the battle known by its more famous name, the Army of the Tennessee) on an invasion up the Tennessee River. (Because of professional and personal animosity toward Grant, Halleck initially designated Grant's subordinate, Maj. Gen. C.F. Smith, to lead the expedition, while Grant sat idly at Fort Henry. After PresidentAbraham Lincoln intervened with Halleck and Smith was injured, Grant was restored to full command.) Grant's orders from Halleck were to link up with Buell's Army of the Ohio, marching from Nashville, and advance south in a joint offensive to seize the Memphis & Charleston Railroad, a vital supply line between the Mississippi River Valley, Memphis, and Richmond.

Grant's army of 48,894 men consisted of six divisions, led by Maj. Gens. John A. McClernand, and Lew Wallace, and Brig. Gens. W.H.L. Wallace, Stephen A. Hurlbut, William T. Sherman, and Benjamin M. Prentiss. Five of the divisions were encamped on the western edge of the Tennessee River. Grant developed a reputation during the war for being more concerned with his own plans than with those of the enemy. His encampment at Pittsburg Landing displayed his most consequential lack of such concern, his army was spread out in bivouac style, many around the small log church named Shiloh (the Hebrew word that means "place of peace"), spending time waiting for Buell with drills for his many raw troops, without entrenchments or other awareness of defensive measures. In his memoirs, Grant reacted to criticism of his lack of entrenchments: "Besides this, the troops with me, officers and men, needed discipline and drill more than they did experience with the pick, shovel and axe. … under all these circumstances I concluded that drill and discipline were worth more to our men than fortifications." Lew Wallace's division was 5 miles (8 km) downstream (north) at Crump's Landing, a position intended to prevent the placement of Confederate river batteries and to strike out at the railroad line at Bethel Station.

On the Confederate side, Johnston named his newly assembled force the Army of Mississippi.He concentrated almost 55,000 men around Corinth, Mississippi, about 20 miles (30 km) southwest of Grant's position. Of these, 44,699 departed from Corinth on April 3, hoping to surprise Grant before Buell arrived to join forces. They were organized into four large corps, commanded by:

On the eve of battle, Grant's and Johnston's armies were of comparable size, but the Confederates were poorly armed with antique weapons, including shotguns, older model smoothbore muskets, and even some pikes. They approached the battle with very little combat experience; Braxton Bragg's men from Pensacola and Mobile were the best trained. Grant's army included 32 out of 62 infantry regiments who had combat experience at Fort Donelson. One half of his artillery batteries and most of his cavalry were also combat veterans.

Johnston's second in command was P.G.T. Beauregard, who urged Johnston not to attack Grant. He was concerned that the sounds of marching and the Confederate soldiers test-firing their rifles after two days of rain had cost them the element of surprise. Johnston refused to accept Beauregard's advice and told him that he would "attack them if they were a million." Despite General Beauregard's well founded concern, the Union forces did not hear the sounds of the marching army in its approach and remained blissfully unaware of the enemy camped 3 miles away.

Johnston's plan was to attack Grant's left and separate the Union army from its gunboat support (and avenue of retreat) on the Tennessee River, driving it west into the swamps of Snake and Owl Creeks, where it could be destroyed. Johnston's attack on Grant was originally planned for April 4, but the advance was delayed 48 hours. As a result, Beauregard again feared that the element of surprise had been lost and recommended withdrawing to Corinth. But Johnston once more refused to consider retreat.

Battle, April 6

Early morning attack

At 6:00 a.m. on April 6 1862, Johnston's army was deployed for battle, straddling the Corinth Road. In fact, the army had spent the entire night bivouacking undetected in order of battle just two miles (3 km) away from the Union camps. Their approach and dawn assault achieved almost total strategic and tactical surprise. The Union army had virtually no patrols in place for early warning. Grant telegraphed to Halleck on the night of April 5, "I have scarcely the faintest idea of an attack (general one) being made upon us, but will be prepared should such a thing take place." Grant's preparedness proved to be overstated. Sherman, Grant's senior commander in the encampment, did not believe that the Confederates were anywhere nearby; he discounted any possibility of an attack from the south, expecting that Johnston would eventually attack from the direction of Purdy, Tennessee, to the west. Early that morning, Benjamin Prentiss had sent forward part of the 25th Missouri Infantry on a reconnaissance, and they became engaged with Confederate outposts at 5:15 a.m. The spirited fight that ensued did help a little to get Union troops better positioned, but the command of the Union army did not prepare properly.

Map of the Battle of Shiloh, morning of April 6, 1862.

The confusing alignment of the Confederate troops helped to reduce the effectiveness of the attack since Johnston and Beauregard had no unified battle plan. Johnston had telegraphed Confederate PresidentJefferson Davis that the attack would proceed as: "Polk the left, Bragg the center, Hardee the right, Breckinridge in reserve." His strategy was to emphasize the attack on his right flank to prevent the Union Army from reaching the Tennessee River, its supply line and avenue of retreat. He instructed Beauregard to stay in the rear and direct men and supplies as needed, while he rode to the front to lead the men on the battle line. This effectively ceded control of the battle to Beauregard, who had a different concept, simply to attack in three waves and push the Union Army straight eastward into the Tennessee River. The corps of Hardee and Bragg began the assault with their divisions in one line, almost 3 miles wide. As these units advanced, they became intermingled and difficult to control. Corps commanders attacked in line without reserves. Artillery could not be concentrated to effect a breakthrough. At about 7:30 a.m. from his position in the rear, Beauregard ordered the corps of Polk and Breckenridge forward on the left and right of the line, diluting their effectiveness. The attack therefore went forward as a frontal assault conducted by a single linear formation, which lacked both the depth and weight needed for success. Command and control in the modern sense were lost from the onset of the first assault.

Grant and Sherman rally

The assault was, despite some shortcomings, ferocious, and some of the many inexperienced Union soldiers of Grant's new army fled for safety to the Tennessee River. Others fought well but were forced to withdraw under strong pressure and attempted to form new defensive lines. Many regiments fragmented entirely; the companies and sections that remained on the field attached themselves to other commands. During this period, Sherman, who had been so negligent in preparation for the battle, became one of its most important elements. He appeared everywhere along his lines, inspiring his raw recruits to resist the initial assaults despite staggering losses on both sides. He received two minor wounds and had three horses shot out from under him. Historian James M. McPherson cites the battle as the turning point of Sherman's life, which helped to make him one of the North's premier generals. Sherman's division bore the brunt of the initial attack, and despite heavy fire on their position and their right flank crumbling, they fought on stubbornly. The Union troops slowly lost ground and fell back to a position behind Shiloh Church. McClernand's division temporarily stabilized the position. Overall, however, Johnston's forces made steady progress until noon, rolling up Union positions one by one.

General Grant was about ten miles (16 km) down river on a gunboat at Savannah, Tennessee, that morning. On April 4, he had been injured when his horse fell and pinned him underneath. He was convalescing and unable to move without crutches. He heard the sound of artillery fire and raced to the battlefield, arriving about 8:30 a.m. He worked frantically to bring up reinforcements that were nearby: Bull Nelson's division from across the river at the Landing; Lew Wallace's division from Crump's Landing. These reserves did not arrive hastily, however, arguably because of the decisions that would be made by Wallace.

Lew Wallace's lost division

Wallace's group had been left as reserves near Crump's Landing at a place called Stoney Lonesome to the rear of the Union line. At the appearance of the Confederates, Grant sent orders for Wallace to move his unit up to support Sherman. Wallace took a route different from the one Grant intended (claiming later that there was ambiguity to Grant's order). Wallace arrived at the end of his march to find that Sherman had been forced back and was no longer where Wallace thought he was. Moreover, the battle line had moved so far that Wallace now found himself in the rear of the advancing Southern troops. A messenger arrived with word that Grant was wondering where Wallace was and why he had not arrived at Pittsburg Landing, where the Union was making its stand. Wallace was confused. He felt sure he could viably launch an attack from where he was and hit the Confederates in the rear; after the war he claimed that his division might have attacked and defeated the Confederates if his advance had not been interrupted. Nevertheless, he decided to turn his troops around and march back to Stoney Lonesome. Rather than realign his troops so that the rear guard would be in the front, Wallace chose to march the troops in a circle so that the original order was maintained, only facing in the other direction. Wallace marched back to Stoney Lonesome and then to Pittsburg Landing, arriving at Grant's position about 6:30 or 7 p.m., when the fighting was practically over. Grant was not pleased, and his endorsement of Wallace's battle report was negative enough to damage Wallace's military career severely.

Hornet's Nest

On the main Union defensive line, starting at about 9:00 a.m., men of Prentiss's and W.H.L. Wallace's divisions established and held a position nicknamed the ''Hornet's Nest'', in a field along a road now popularly called the "Sunken Road," although there is little physical justification for that name. The Confederates assaulted the position for several hours rather than simply bypassing it, and they suffered heavy casualties during these assaults. The Union forces to the left and right of the Nest were forced back, and Prentiss's position became a salient in the line.Coordination among units in the Nest was poor, and units withdrew based solely on their individual commanders' decisions. This pressure increased with the mortal wounding of Wallace, who commanded the largest concentration of troops in the position. Regiments became disorganized and companies disintegrated. However, it was not until the attackers assembled over 50 cannons to blast the line that they were able to surround the position, and the Hornet's Nest fell after holding for seven hours. A large portion of the Union survivors were captured, but their sacrifice bought time for Grant to establish a final defense line near Pittsburg Landing.

Map of the Battle of Shiloh, afternoon of April 6, 1862.

Part of the problem in dealing with the Hornet's Nest involved another setback for the South. Johnston was mortally wounded at about 2:30 p.m. while leading attacks on the Union left. He had sent his personal surgeon away to care for some wounded soldiers, and in the doctor's absence, he bled to death from a leg wound that did not seem serious at first, his boot filling with blood. This was a significant loss for the Confederacy. Jefferson Davis considered Albert Sidney Johnston to be the most effective general they had. (This was two months before Robert E. Lee emerged as the pre-eminent Confederate general.) Beauregard assumed command, but from his position in the rear he may have had only a vague idea of the disposition of forces at the front. He ordered Johnston's body shrouded for secrecy to avoid damaging morale in the army and then resumed attacks against the Hornet's Nest. This was likely a tactical error. The Union flanks were slowly pulling back to form a semicircular line around Pittsburg Landing, and if Beauregard had concentrated his forces against the flanks, he might have defeated the Union Army and then reduced the Hornet's Nest salient at his leisure.

Defense at Pittsburg Landing

The Union flanks were being pushed back, but not decisively. Hardee and Polk caused Sherman and McClernand on the Union right to retreat in the direction of Pittsburg Landing, leaving the right flank of the Hornet's Nest exposed. Just after the death of Johnston, Breckinridge, whose corps had been in reserve, attacked on the extreme left of the Union line, driving off the understrength brigade of Colonel David Stuart and potentially opening a path into the Union rear area and the Tennessee River. However, they paused to regroup and recover from exhaustion and disorganization, and then chose to follow the sound of the guns toward the Hornet's Nest, and an opportunity was lost. After the Hornet's Nest fell, the remnants of the Union line established a solid three-mile (5 km) front around Pittsburg Landing, extending west from the Tennessee and then north up the River Road, keeping the approach open for the expected belated arrival of Lew Wallace's division. Sherman commanded the right of the line, McClernand the center, and on the left, remnants of W.H.L. Wallace's, Hurlbut's, and Stuart's men mixed in with the thousands of stragglers who were crowding on the bluff over the landing. One brigade of Buell's army, Brig. Gen. Jacob Ammen's brigade of Bull Nelson's division, arrived in time to be ferried over and join the left end of the line. The defensive line included a ring of over 50 cannons and naval guns from the river (the gunboats USS Lexington and USS Tyler). A final Confederate charge of two brigades, led by Brig. Gen. Withers, attempted to break through the line but was repulsed. Beauregard called off a second attempt after 6 p.m., with the sun setting. The Confederate plan had failed; they had pushed Grant east to a defensible position on the river, not forced him west into the swamps.

Evening lull

The evening of April 6 was a dispiriting end to the first day of one of the bloodiest battles in U.S. history. The desperate screams of soldiers dying on the fields between the armies could be heard in the Union and Confederate camps throughout the night. A thunderstorm passed through the area and rhythmic shelling from the Union gunboats made the night a miserable experience for both sides. A famous anecdote encapsulates Grant's unflinching attitude to temporary setbacks and his tendency for offensive action. As the exhausted Confederate soldiers bedded down in the abandoned Union camps, Sherman encountered Grant under a tree, sheltering himself from the pouring rain. He was smoking one of his cigars while considering his losses and planning for the next day. Sherman remarked, "Well, Grant, we've had the devil's own day, haven't we?" Grant looked up. "Yes," he replied, followed by a puff. "Yes. Lick 'em tomorrow, though."<ref>Smith, p. 201; Sword, pp. 369-82.</ref>

Beauregard sent a telegram to President Davis announcing "A COMPLETE VICTORY" and later admitted, "I thought I had General Grant just where I wanted him and could finish him up in the morning." Many of his men were jubilant, having overrun the Union camps and taken thousands of prisoners and tons of supplies. But Grant had reason to be optimistic, for Lew Wallace's division and 15,000 men of Don Carlos Buell's army began to arrive that evening, with Buell's men fully on the scene by 4 a.m., in time to turn the tide the next day. Beauregard caused considerable historical controversy with his decision to halt the assault at dusk. Braxton Bragg and Sidney Johnston's son, Col. William Preston Johnston, were among those who bemoaned the so-called "lost opportunity at Shiloh." Beauregard did not come to the front to inspect the strength of the Union lines but remained at Shiloh Church. He also discounted intelligence reports from Col. Nathan Bedford Forrest (and bluster from prisoner of war Gen. Prentiss) that Buell's men were crossing the river to reinforce Grant. In defense of his decision, his troops were simply exhausted, there was less than an hour of daylight left, and Grant's artillery advantage was formidable. He had also received a dispatch from Brig. Gen. Benjamin Hardin Helm in northern Alabama, indicating that Buell was marching toward Decatur and not Pittsburg Landing.

Battle, April 7

On April 7, 1862, the combined Union armies numbered 45,000 men. The Confederates had suffered heavy losses during the first day, as many as 8,500, but because of straggling and desertion, their commanders reported no more than 20,000 effectives; Buell disputed that figure after the war, claiming that there were 28,000. The Southern soldiers had withdrawn south into Prentiss's and Sherman's camps, and Polk's corps retired all the way to the April 5 Confederate bivouac, 4 miles (6.5 km) southwest of Pittsburg Landing. No line of battle was formed, and few if any commands were resupplied with ammunition. The soldiers were consumed by the need to locate food, water, and shelter for a much-needed night's rest.

Beauregard, unaware that he was now outnumbered, planned to continue the attack and drive Grant into the river. To his surprise, Union forces started moving forward in a massive counterattack at dawn; Grant and Buell launched their attacks separately; coordination occurred only down at the division level. Lew Wallace's division was the first to see action, at the extreme right of the Union line, crossing Tilghman Branch around 7 a.m. and driving back the brigade of Col. Preston Pond. On Wallace's left were the survivors of Sherman's division, then McClernand's, and W.H.L. Wallace's (now under the command of Col. James Tuttle). Buell's divisions continued to the left: Bull Nelson's, Crittenden's, and McCook's. The Confederate defenders were so badly commingled that little unit cohesion existed above the brigade level. It required over two hours to locate Gen. Polk and bring up his division from its bivouac to the southwest. By 10 a.m., Beauregard had stabilized his front with his corps commanders from left to right: Bragg, Polk, Breckinridge, and Hardee.

Map of the Battle of Shiloh, afternoon of April 6, 1862.

On the Union left, Nelson's division led the advance, followed closely by Crittenden's and McCook's, down the Corinth and Hamburg-Savannah Roads. After heavy fighting, Crittenden's division recaptured the Hornet's Nest area by late morning, but Crittenden and Nelson were both repulsed by determined counterattacks launched by Breckinridge. The Union right made steady progress, driving Bragg and Polk to the south. As Crittenden and McCook resumed their attacks, Breckenridge was forced to retire, and by noon Beauregard's line paralleled the Hamburg-Purdy Road.

In early afternoon, Beauregard launched a series of counterattacks from the Shiloh Church area, aiming to ensure control of the Corinth Road. The Union right was temporarily driven back by these assaults at Water Oaks Pond. Crittenden, reinforced by Tuttle, seized the road junction of the Hamburg-Purdy and East Corinth Roads, driving the Confederates into Prentiss's old camps. Nelson resumed his attack and seized the heights overlooking Locust Grove Branch by late afternoon. Beauregard's final counterattack was flanked and repulsed when Grant moved Col. James C. Veatch's brigade forward.<ref>Daniel, pp. 283-87.</ref>

Realizing that he had lost the initiative and that he was low on ammunition and food and with over 10,000 of his men killed, wounded, or missing, Beauregard knew he could go no further. He withdrew beyond Shiloh Church, using 5,000 men under Breckenridge as a covering force, massing Confederate batteries at the church and on the ridge south of Shiloh Branch. These forces kept the Union forces in position on the Corinth Road until 5 p.m., when the Confederates began an orderly withdrawal back to Corinth. The exhausted Union soldiers did not pursue much past the original Sherman and Prentiss encampments; Lew Wallace's division advanced beyond Shiloh Branch but, receiving no support from other units, halted at dark and returned to Sherman's camp. The battle was over. For long afterwards, Grant and Buell quarreled over Grant's decision not to mount an immediate pursuit with another hour of daylight remaining. Grant cited the exhaustion of his troops, although the Confederates were certainly just as exhausted. Part of Grant's reluctance to act could have been the unusual command relationship he had with Buell. Although Grant was the senior officer and technically was in command of both armies, Buell made it quite clear throughout the two days that he was acting independently.

Fallen Timbers, April 8

On April 8, Grant sent Sherman south along the Corinth Road on a reconnaissance in force to ascertain if the Confederates had retreated or if they were regrouping to resume their attacks. Grant's army lacked the large organized cavalry units that would have been better suited for reconnaissance and for vigorous pursuit of a retreating enemy. Sherman marched with two infantry brigades from his division, along with two battalions of cavalry, and they met up with Brig. Gen. [[[Thomas J. Woods]]'s division of Buell's army. Six miles (10 km) southwest of Pittsburg Landing, Sherman's men came upon a clear field in which an extensive camp was erected, including a Confederate field hospital, protected by 300 troopers of Southern cavalry, commanded by Col. Nathan Bedford Forrest. The road approaching the field was covered by fallen trees for over 200 yards.

As skirmishers from the 77th Ohio Infantry approached, having difficulty clearing the fallen timber, Forrest ordered a charge, producing a wild melee with Southern troopers firing shotguns and revolvers and brandishing sabers, nearly resulting in the capture of Sherman. As Col. Jesse Hildebrand's brigade began forming in line of battle, the Southern troopers started to retreat at the sight of the strong force, and Forrest, who was well in advance of his men, came within a few yards of the Union soldiers before realizing he was all alone. Sherman's men yelled out, "Kill him! Kill him and his horse!" A Union soldier shoved his musket into Forrest's side and fired, striking him above the hip, penetrating to the spine. Although he was seriously wounded, Forrest was able to stay on horseback and escape; he survived both the wound and the war. The Union lost about 100 men, mostly captured during Forrest's charge, in an incident that has been remembered with the name "Fallen Timbers". After capturing the Confederate field hospital, Sherman encountered the rear of Breckinridge's covering force and, determining that the enemy was making no signs of renewing its attack, withdrew back to camp.

Aftermath

In the immediate aftermath of the battle, Northern newspapers vilified Grant for his performance during the battle on April 6. Reporters, many far from the battle, spread the story that Grant had been drunk, falsely alleging that this had resulted in many of his men being [[[bayonet|bayoneted]] in their tents because of a lack of defensive preparedness. Despite the Union victory, Grant's reputation suffered in Northern public opinion. Many credited Buell with taking control of the broken Union forces and leading them to victory on April 7. Calls for Grant's removal overwhelmed the White House. PresidentAbraham Lincoln replied with one of his most famous quotations about Grant: "I can't spare this man; he fights." Sherman emerged as an immediate hero, his steadfastness under fire and chaos atoning for his previous melancholy and his defensive lapses preceding the battle. Today, however, Grant is recognized positively for the clear judgment he was able to retain under the strenuous circumstances, and his ability to perceive the larger tactical picture that ultimately resulted in victory on the second day.

Nevertheless, Grant's career suffered temporarily in the aftermath of Shiloh. Henry W. Halleck combined and reorganized his armies, relegating Grant to the powerless position of second-in-command. In late April and May the Union armies, under Halleck's personal command, advanced slowly toward Corinth and captured it, while an amphibious force on the Mississippi River destroyed the Confederate River Defense Fleet and captured Memphis. Halleck was promoted to be general in chief of all the Union armies, and with his departure for the East, Grant was restored to command. Grant pushed on down the Mississippi to besiege Vicksburg. After the surrender of Vicksburg and the fall of Port Hudson in the summer of 1863, the Mississippi was under Union control and the Confederacy was cut in half. Command of the Army of Mississippi fell to Braxton Bragg, who was promoted to full general on April 6. In the fall, he led it on an unsuccessful invasion of Kentucky, culminating in his retreat from the Battle of Perryville.

The two-day battle of Shiloh, the costliest in U.S. history up to that time, resulted in the defeat of the Confederate army and frustration of Johnston's plans to prevent the joining of the two Union armies in Tennessee. Union casualties were 13,047 (1,754 killed, 8,408 wounded, and 2,885 missing); Grant's army bore the brunt of the fighting over the two days, with casualties of 1,513 killed, 6,601 wounded, and 2,830 missing or captured. Confederate casualties were 10,699 (1,728 killed, 8,012 wounded, and 959 missing or captured). This total of 23,746 men represented more than the American battle-related casualties of the American Revolutionary War, the War of 1812, and the Mexican-American War combined. The dead included the Confederate army's commander, Albert Sidney Johnston; the highest ranking Union general killed was W.H.L. Wallace. Both sides were shocked at the carnage. None suspected that three more years of such bloodshed remained in the war and that eight larger and bloodier battles were yet to come. (The eight battles with higher casualties than Shiloh were: Gettysburg, Chickamauga, Chancellorsville, Spotsylvania, Antietam, Wilderness, Second Bull Run, and Stones River.) Grant came to realize that his prediction of one great battle bringing the war to a close was probably not destined to happen. The war would continue, at great cost in casualties and resources, until the Confederacy succumbed or the Union was divided. Grant also learned a valuable personal lesson on preparedness that (mostly) served him well for the rest of the war.